Cameras are prevalent in smartphones and other electronic devices that are relatively compact. The flash for the camera is typically formed of one or two phosphor-converted, white-light light emitting diodes (“LEDs”). The total combined area of the LEDs typically determines the instantaneous brightness of the flash for a given driving current pulse. The bare LED die is GaN-based and emits blue light, and the phosphor (typically YAG) adds a yellow component (or red and green components). The combination of the blue light leaking through the phosphor and the light provided by the phosphor itself creates the bright white light for the flash.
The camera flash typically uses a tiny Fresnel lens or other type of molded plastic lens to collimate the light in an attempt to direct most of the light at the subject in the field of view of the camera. The flash lenses are typically small, and the LED is off to one side of the camera lens. Due to the difficulties in designing small flash units, the lighting quality produced by LED flash units is typically low. Improvements in LED flashes for small cameras are needed.